Juvenile Myelomonocytic Leukemia

National Organization for Rare Disorders, Inc.

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It is possible that the main title of the report Juvenile Myelomonocytic Leukemia is not the name you expected.

Disorder Subdivisions

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General Discussion


Juvenile myelomonocytic leukemia (JMML) is a rare pediatric form of blood cancer. JMML predominately affects young children, most often developing in children under the age of 4. The male/female ratio of affected children is 2-3:1.The disorder is characterized by the uncontrolled growth of an immature form of a specific type of white blood cell known as monocyte precursors. These abnormal cells accumulate in the bone marrow crowding out other healthy cells. The bone marrow produces specialized cells (hematopoietic stem cells) that grow and eventually develop into red blood cells, white blood cells and platelets. These cells are released into the bloodstream to travel throughout the body and perform specific functions. Red blood cells deliver oxygen to the body; white blood cells help the body to fight infection; and platelets allow the body to form clots to stop bleeding. When abnormal cells accumulate in the bone marrow, they can affect the production and function of these healthy blood cells. Abnormal cells can accumulate in other tissues and organs of the body such as the lungs, skin, liver, and intestines. JMML is an aggressive and difficult to treat disease. Currently, the main therapeutic option is allogeneic hematopoietic stem cell transplantation. The exact, underlying cause of JMML is unknown.


Over the years, several different classification systems have been used to define JMML. Currently, the World Health Organization (WHO) classifies JMML as an overlap myelodysplastic syndrome/myeloproliferative disorder because JMML shares characteristics with both of these groups of disorders. Myelodysplastic syndromes are defined as a group of disorders that are characterized by disordered development of blood cells in the bone marrow. Myeloproliferative disorders are defined as a group of disorders characterized by the overproduction (proliferation) of the three main blood cell lines, red or white blood cells or platelets. The first case of JMML was described in the medical literature in 1924.

Supporting Organizations

American Cancer Society, Inc.

250 Williams NW St
Ste 6000
Atlanta, GA 30303
Tel: (404)320-3333
Tel: (800)227-2345
Website: http://www.cancer.org

Children's Leukemia Research Association

585 Stewart Avenue, Suite 18
Garden City, NY 11530
Tel: (516)222-1944
Fax: (516)222-0457
Email: info@childrensleukemia.org
Website: http://www.childrensleukemia.org

Children's Tumor Foundation

120 Wall Street
16th Floor
New York, NY 10005
Tel: (212) 344-6633
Fax: (212)747-0004
Tel: (800)323-7938
Email: info@ctf.org
Website: http://www.ctf.org/

JMML Foundation

Website: http://thejmmlfoundation.wildapricot.org/

Leukemia & Lymphoma Society

1311 Mamaroneck Avenue
Suite 310
White Plains, NY 10605
Tel: (914)949-5213
Fax: (914)949-6691
Tel: (800)955-4572
Email: infocenter@LLS.org
Website: http://www.LLS.org

National Bone Marrow Transplant Link

20411 W. 12 Mile Rd
Suite 108
Southfield, MI 48076
Tel: (248)358-1886
Fax: (248)358-1889
Tel: (800)546-5268
Email: info@nbmtlink.org
Website: http://www.nbmtlink.org

OncoLink: The University of Pennsylvania Cancer Center Resource

3400 Spruce Street
2 Donner
Philadelphia, PA 19104-4283
Tel: (215)349-8895
Fax: (215)349-5445
Email: hampshire@uphs.upenn.edu
Website: http://www.oncolink.upenn.edu

Rare Cancer Alliance

1649 North Pacana Way
Green Valley, AZ 85614
Website: http://www.rare-cancer.org

World Health Organization (WHO)

Avenue Appia 20
Geneva 27, 1211
Tel: 41227912111
Fax: 41227913111
Website: http://www.who.int/en/

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders (NORD). For a full-text version of this report, go to www.rarediseases.org and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only.

It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report.

This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

Last Updated:  5/8/2013
Copyright  2013 National Organization for Rare Disorders, Inc.